The present invention relates to heat insulating sheets for car door windows, and relates more particularly to such a heat insulating sheet which can be conveniently installed in the window glass and, which does not drop from the window glass when the window glass passes in and out of the car door frame.
In order to prevent direction radiation of the light of the sun, heat insulating sheets may be used and installed in car door windows. However, it is not easy to fasten a heat insulating sheet to the window glass. When a heat insulating sheet is adhered to the window glass, it cannot be conveniently removed from the window glass for a replacement. Furthermore, when the window glass is lowered, the heat insulating sheet tends to be forced away from the window glass by the rubber packing strip of the car door window. U.S. Pat. No. 5,016,936 discloses a replaceable heat insulating paper for car door windows which can be conveniently attached to the window glass and then removed from it. However, in order to make the heat insulating paper convenient to be removed from the window glass, its adhesion power is made less strong, thereby causing the heat insulating paper to be easily forced away from the window glass by the rubber packing strip of the car door window when it is lowered with the window glass.